1. Field of the Invention
The present invention relates to filtration of liquid media and particularly to filtration of water or the like.
2. State of the Art
Filtration apparatus is known for filtering water. Such apparatus typically comprises a vessel pressurised with water having an inlet, a bed of filter media (typically one or more layers of graded sand or other particulate material), and an outlet drain arrangement for directing off the filtered water. In order to periodically clean the filter media a cleaning backwash is forced through the drain arrangement (typically causing fluidisation of the bed of filter media) and the backwashed liquid is drawn off to waste above the level of the bed of filter media.
An improved technique and system has now been devised.